[9] RFR of 6880737: (fs) FileLock constructors don't throw NPE if the channel argument is null

[Brian Burkhalter]

Hello,

Please review at your convenience.

Issue:	https://bugs.openjdk.java.net/browse/JDK-6880737
Patch:	http://cr.openjdk.java.net/~bpb/6880737/webrev.00/

This is a minor change to check the channel parameter of FileLock(). Although this class is public, a non-JDK subclass does not appear to be able to be used via any JDK API so the effect of the change should be innocuous. The minor change to the channel parameter specification should not, I would think, merit a CCC request.

Thanks,

Brian